King Air Operation on Unimproved Landing Strips

I am sure many of my readers have a great deal more experience than I have in operating King Airs in remote areas where paved runways are few and far between. In fact, I’d wager that for many years now the King Air has been perhaps the most popular airplane in commercial service doing this type of work worldwide. Northern Canada, the Outback of Australia, Medivac work in remote areas in this country and elsewhere, war zones … you will find King Airs in all of these places providing dependable and safe service.

Although my routine flying has mostly been from full-service airports, I have been fortunate to experience quite a few not-so-nice locations in my 44 years of King Air operation.  A few that come to mind are Las Cruces and others on the southern Baja coast of Mexico, quite a few of the backcountry strips in Idaho, and remote areas of Alaska and Canada. Granted, not all runways in remote areas are unimproved. In fact, some are quite nice. However, the chance of finding a rough one tends to increase in direct proportion to how far it is from civilization.

The intent of this article is to present some procedures and techniques that help allow this type of operation to be conducted with minimum additional risk of harm to the airplane and its crew and passengers.

Before I discuss specific King Air procedures, it is important to remind us of the considerations that apply to any and all airplane operations in these types of environments. Weather, fuel, weight and balance, and alternative courses of action are four important considerations for all flights, but they take on added significance as the remoteness factor increases.

Weather: Keep in mind that reporting sites may be quite scattered. Also, the wonderful downlink weather that has had such a huge positive impact on our real-time weather knowledge in the last couple of decades may not be available. Being able to place a telephone, HF or satphone call to a person at the destination airport can be wonderful help. Unfortunately, that capability does not always exist either due to the lack of equipment or the lack of a person to accept the call. Even when we do make contact with a person at the airport, the information we receive may be quite outdated by the time we arrive.

Fuel: To get to and from the remote location involves careful fuel planning since the options of refueling places may be quite limited and the weather situation may be more unknown than we’d like. There is a strong urge to tanker a lot of fuel yet that urge is counterbalanced oftentimes with the recognition that the remote strip’s length is short and safety is negatively impacted the heavier we are when departing.

Weight and Balance: This routine consideration for every flight operation usually takes on more significance here due to the length and condition of the remote strip, and the uncertainty of what we may find there. For example, did a recent downpour wash out one end? Did the passengers we’re picking up have a really successful trip and hence have a couple of hundred extra pounds of meat or fish to fly out? Did they make friends with a couple at the lodge and offered them a free flight out? It is amazing how often “the best laid plans” seem to go awry.

Alternates and Alternatives: Of course we will want to have an alternate airport in mind. What if the Otter landing before us ground-looped and is sitting in the middle of the runway? What if the weather turned so bad that we never saw the runway? But also, even with a usable and visible runway, what alternatives should be considered when the unexpected happens? “Wow, the wind was not nearly what was forecast!” Or, “We’re going to need to make another trip. No way can we depart with that extra meat and passengers.”

Being legal and safe … these considerations apply to all operations at all times. Yes, there are times and events that make it difficult, perhaps impossible, to dot all of the i’s and cross all of the t’s. As I relate in The King Air Book, when I was being briefed before the ferry flight of the three 350s from Wichita to Japan – via the northern route through Siberia – I’ll never forget the comment, “We don’t make missed approaches.” When the nearest alternate airport may be over 500 miles away, landing at the planned destination can become mandatory … one way or another.

Now let’s get King Air specific. What techniques can we use that will protect the plane and its occupants from unnecessary wear and tear and worry?

Starting: It is not uncommon to find a paved parking and run-up pad at a remote strip and when that unexpected bonus exists, using it can eliminate the need for any change in starting technique. Got a broom? It’s nice to be able to sweep the pad clean of gravel and dust that was blown up in the last storm.

Engine ice vanes were extended before we landed and have remained extended ever since. Although this has become common practice on the newer King Airs with their four-bladed propellers and higher idle speeds, even on paved surfaces, it is still an abnormal procedure for older three-bladed models with the chin-style cowling. Do it now.

When no pad exists – or it is already occupied – then we are forced to start on the dirt/gravel/sand surface. Grass? Firm turf with a nice coating of grass is as benign as a paved surface for starting, so have at it using normal procedures. The problem with grass is that we often don’t know how firm or soft it is by visual inspection while taxiing in after the previous landing. It is necessary at times to shut down before we exit the firm runway and to give the prospective parking spot a careful walk-over to help decide if it is firm enough for our usage. If in doubt, avoid.

So now we are on that dirt/gravel/sand surface that cannot be swept clean with a broom. Time to start engines. What changes should we make?

I suggest two differences. First, start the left engine first. Although we hope that no rocks will be picked up by the propeller, on a surface like this it is a possibility even with the best of techniques. The clockwise spinning props – as viewed from the back – mean that the blade is moving right-to-left as it passes closest to the ground. If a rock is in fact picked up by the prop,
it should be displaced to the left, away from the nose. On the other hand, the right side’s propeller tends to hurl any rock right into the nose, nose gear door, or other forward part of the plane.

Second, remain at Low Idle and conduct two battery starts without using a generator to recharge between the starts. Sure, this puts more drain on the battery, but it can handle it without problems. Yes, the second engine will not benefit from a generator assist, so the stabilized speed will be lower and the peak ITT will be higher … but well within comfortable limits.

The reason we “must” forego the generator usage is that N1 versus generator load limits will be exceeded unless we go to High Idle on the left engine. Although the propeller-disturbed air at Low Idle will not guarantee no rock damage in all cases, High Idle will almost assure that there will be some rock damage … if not to the nose, then to a propeller blade or blades. The difference in disturbed air factor between Low and High Idle is greater when the Low Idles are set close to 50 percent N1, as on the older three-blade-propeller airplanes. The difference is not as dramatic on four-blade-propeller airplanes since their Low Idles are set closer to 60 percent, yet all High Idles are near 70 percent.

How about starting in feather to keep RPM, wind, and noise down, so there is less dirt/gravel/sand displaced? There is absolutely no question that RPM and noise will be less. As for wind? Of course, the normal prop wash blowing back over the nacelle and wing is eliminated but how about the “wind” the ground feels as the blade makes that right-to-left pass? In most cases this will actually be greater in feather, the exception being the three-blade models with their low Low Idle speed.

I suggest not starting in feather on these surfaces until you conduct a simple test. In your own King Air, wait for a rainy day and find a puddle as you taxi to or from a flight on a paved ramp/taxiway. Stop with your left prop over the puddle. See how much water is displaced while sitting there at Low Idle. Now feather the prop and see what is now happening to the water. Of course, how much surface wind exists and its direction will affect these results so realize that what you are observing won’t always be the same when dirt replaces the water and the existing wind changes. Nevertheless, you will probably conclude that the feathered prop blades do not offer much, if any, benefit in this situation.

After the right engine has completed its battery-only start and is stable at Low Idle, now is the time to turn on the generators. Although doing them one-at-a-time is fine, there is nothing wrong with activating both switches simultaneously. That’s the technique I use. Keep in mind your Low Idle ITT limit since ITT will rise due to the generator load. For it to reach the Low Idle limit is extremely rare, likely only with three-blade props and their minimum Low Idles. When King Airs had NiCad batteries – and a few still do! – the initial generator load went higher than it does with the current Lead-Acid batteries, so the odds of exceeding the ITT limit were slightly increased.

Even though only one reader in a hundred may observe ITT rising to and trying to exceed the Low Idle limit, we must be prepared for that uncommon occurrence. What to do? Turn off the generators, of course! Next, take the condition levers and add about five percent N1 to both engines and try the generators on again. The ITT still tries to pass the limit? (And this is extremely unlikely!) Turn the generators off again while you add another five percent or so, and try again.

Some of my readers may be wondering why running the compressor faster – which requires more fuel flow – would lower ITT. Realize that as compressor speed increases, the engine receives more air and three-fourths of that air is used for cooling not combustion. It turns out that up to High Idle, 70 percent N1, the cooling effect of the air is greater than the heating effect of the fuel. Cool!

(As a side note: One of my King Air pet peeves is that the Low Idle ITT limit is not marked or placarded in the cockpit in any manner whatsoever! Unless you’ve studied the POH with an eagle eye or received thorough training, it’s a mystery. Well, let me just give them to you: PT6A-20, -20A, -135, -135A: 685° C; -21, -28, -41: 660° C; -42, -52, -60A: 750° C. Notice that all of these are well below the top of the gauge’s redline.)

Before Takeoff Checks: This is not the time for doing all of the first-flight-of-the-day ground checks! That is nearly a guarantee that you will be leaving rock dings on propeller blades, gear doors, flaps, and maybe elsewhere. If you cannot accept this fact and forego the checks, then remote strip operation is not for you. Shorten down to some version of CIGAR, make sure the gyros are all erected and the avionics are set, and let’s hit the road!

During this rather brief ground operating period, in most cases leave the air conditioning off. We may not have enough N1 speed to handle the load and, if the runway is short, we’ll want it off for takeoff anyway. A little extra cabin temperature is something that is often unavoidable on short desert and jungle strips. Airborne? Ah, now we can use whatever we want.

Taxiing: We release the brakes and prepare to add that little burst of power to get us moving. Stop! Don’t push those power levers forward! There’s a much better way. A quick increase in propeller blade angle will be just the ticket to provide enough burst of thrust to get the airplane rolling and it causes a decrease, not an increase, in RPM.

Model 300 pilots have it the easiest here: Just tap the “Turbo Boost” switch up momentarily. That’s the slang term I give to the “Grd Idle Stop Test” switch that makes the blade angle jump from the Ground to the Flight Low Pitch Stop (LPS), an increase of about 12 degrees. The model 300s with the updated/modified LPS system and all 350s have to add a little power to move to the Flight LPS and we want to avoid that increase in RPM. Hence, all models other than the 300 can do it this way: Just a quick pull of both propeller levers into and immediately out of the feather detent. Hey! Look at that! She started rolling just great with no power increase, thanks to that sudden increase in propeller bite!

While taxiing, avoid use of any Beta unless you are now rolling on a reasonably good surface. Just leave the power levers at Idle and ride the brakes or coast with the propellers pulled into feather. In situations like this, additional brake wear is the price we pay for protecting the propeller blades.

Try to keep the airplane moving until right up to the start of the takeoff roll. If you are forced to stop – waiting for other traffic, perhaps – then use the technique presented above to start rolling again.

The Takeoff: Will we use approach flaps? That depends both on the length and the roughness condition of the runway. Keep in mind that most of the 90-series King Airs have no POH data for takeoff with approach flaps. If you decide that flaps are advantageous, wait to extend them until taking the runway so as to better avoid rock hits onto the extended flaps. Some pilots wait to extend the flaps until actually rolling down the runway. That’s a poor technique for two reasons: First, our attention must be divided as we check the flap indicator to verify that the flaps did what we wanted them to do. Second, what if we have a split flap situation? Will we recognize it quickly enough to abort, or will we discover the surprise only after we rotate? I want to make absolutely sure that the flaps are behaving themselves before I start the takeoff roll.

Ice Vanes? Many pilots want to leave the vanes extended for takeoff to better protect the engine from FOD, Foreign Object Damage. However, with the combination of forward velocity and a positive propeller blade bite, FOD is impossible. If the altitude and OAT are such that your engines can make full power even with the vanes extended – “Engine Anti-Ice On” for the later models – then I suggest leaving them extended just in case we abort the takeoff and use Ground Fine or Reverse to help stop. On the other hand, an old PT6A-20-powered A90, in the summer in Baja, will be ITT-limited and the vanes will cause a slight reduction in takeoff power, so I would vote for retracting them on the runway. If we abort, make sure we leave Reverse no later than 40 KIAS…unless doing so will cause us to “crash” off the end of the short runway. Repairing engine FOD will be less expensive than repairing bent props and broken landing gear!

Landing: I know this may seem out of order, since we must have landed on this marginal strip before we had to depart. Yes, of course, but I chose to start the discussion with the start-up, taxi, and departure so I have saved this for last.

Engine anti-ice, ice vanes, should be extended before we touch down. For some models, this is routine practice; for others, it is not. Even though the advantage of extended ice vanes may be small when proper use of Beta and Reverse is used, there is almost no downside to their use.

Run the propeller levers full forward before touchdown. Here is a case in which Maximum Reverse may be utilized and having the prop levers forward before doing so is imperative. Sure, it’s noisier, but so what?

Back to the issue of FOD: The chance of FOD is so small as to be nearly impossible if (A) we are moving fast enough that any disturbed ground debris will be left behind, or (B) our propeller blade angle is positive, not stirring up debris and blowing it forward. So the proper technique for using Reverse here is “Full and Fast, then Out.” By that, I mean lift those power levers immediately at touchdown and rapidly move them all the way aft and down to Maximum Reverse. (Later models require the second lift to pass behind Ground Fine.) It has been my observation through thousands of training flights that few pilots get the levers all the way back and down. Realize that, due to the arc the levers move through, the last bit of travel is achieved more by pushing toward the floor than by pulling toward the baggage compartment!

Now, as you see the IAS hit 60 knots, start moving the power levers up and forward so that we are out of Reverse by 40 KIAS. On a paved runway, this is where you want to be at Ground Fine or “Top of the Stripes.” However, if this is an unpaved strip with lots of dirt/gravel/sand then, as in taxiing, we want to be all the way to Idle, even though it will require additional brake usage.

Another procedure that helps on these types of landings is the immediate retraction of flaps at touchdown. Having a copilot to work the flaps is ideal, but even when operating single-pilot, I suggest taking your hand off of the power levers after Max Reverse has been attained, moving the flap switch fully up, then returning to the power levers. Two benefits are derived in so doing: First, the airplane anchors more solidly to the runway and, when brakes are used, there is less chance of locking up and scuffing or blowing a tire. Second, the flaps have less exposure to damage from rocks kicked up by the main tires.

Yes, it goes without saying that grabbing the gear handle instead of the flap handle is a horrible, expensive, mistake and that’s why doing the flap retraction in normal, single-pilot, operation is rarely considered to be a good thing. Here, however, it makes sense. In a King Air, it is comforting to realize that the flap handle and gear handle are in very different locations. Keep your hand on the power quadrant, don’t reach forward to the subpanel!

In closing, years ago when I was based in Hayward, California, one of my King Air training customers was an owner-pilot of a sweet C90 that he loved to use for trips to the many dirt strips by the ocean in Baja. When he returned from these trips – my goodness! – Beechcraft West, the Beech dealer based there who serviced the plane, would spend days fixing the airplane! Almost always all prop blades had to be filed, flaps and gear doors were patched and painted as needed, and the engine compressors were always checked for evidence of FOD. I suggested that the owner take my wife and me on one of his extended weekend getaways and let me demonstrate some techniques that I was sure would alleviate these post-trip maintenance nightmares. He immediately accepted my suggestion and I presented to him, via demonstration and practice, what you have read here. Amazing! From that point on, Beechcraft West found themselves with little if anything to address when the plane returned.

I hope you will consider these techniques and incorporate them into your procedures for use on unimproved strips. They really do work!